So you may have heard of Pay it Forward, or Opras Angels. WakeUp Sydney have a similar thing going where you may join and log into thier site and order random acts of kindness cards.
The idea is that you do something nice for someone, leave the card behind and let them find what you have done and the card. They get a nice surprise for the day and hopefully they do something similar for someone else.
We need more of this around in my opinion, please help raise awareness for these kinds of causes by signing up to WakeUp Sydney and ordering your cards.